Autostereoscopic display with fresnel lens element

ABSTRACT

An autostereoscopic display is described. The autostereoscopic display apparatus includes a backlight having opposing first and second light input surfaces and a light transmission surface extending between the opposing first and second light input surfaces and a right eye light source located to provide light into the first light input side and a left eye light source located to provide light into the second light input side, wherein the left eye light source and the right eye light source are configured to be modulated between the left eye light source and the right eye light source at a rate of at least 90 hertz. A double sided prism film is adjacent to the light transmission surface. The double sided prism film has a plurality of linear prism features on a first major surface and a plurality of lenticular features on a second major surface. The first major surface opposes the second major surface. The double sided prism film is disposed between the light transmission surface and a Fresnel lens element. A liquid crystal display panel is positioned to receive light transmitted through the double sided prism film.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Ser. No. 12/051,509, filedMar. 19, 2008, now allowed, the disclosure of which is incorporated byreference in its entirety herein.

FIELD

The present disclosure relates to autostereoscopic displays that includea Fresnel lens element.

BACKGROUND

A stereoscopic display usually presents an observer with images withparallax from individual right and left eye viewpoints. There are twomethods of providing the two eyes of the observer with the parallaximages. In one method, the observer utilizes a pair of shutter or 3Dglasses which transmit or block light from the viewer's eyes insynchronization with alternating the left/right image display.Similarly, in another method, right eye and left eye viewpoints arealternatively displayed and led to the respective eyes of the observerbut without the use of 3D glasses. This second method is referred to asautostereoscopic and is desired for stereo 3D viewing because separateglasses are not needed.

A liquid crystal display (LCD) is a sample and hold display device suchthat the image at any point or pixel of the display is stable until thatpixel is updated at the next image refresh time, typically 1/60 of asecond or faster. In such a sample and hold system, displaying differentimages, specifically displaying alternating left and right images for anautostereoscopic display, requires careful timing sequencing of thelight sources so that, for example, the left eye image light source isnot on during the display of data for the right eye and vice versa.

Ensuring that the right and left light sources are on or off insynchronization with the image display is important to achieve a highquality autostereoscopic image. As these displays increase in size, theedge portions of the display exhibit a reduced quality autostereoscopicimage. These large format displays do not provide a uniform qualityautostereoscopic image across the width of the display since the anglebetween the edge of the display and the center of the display at theviewer position is too great. Therefore, improvements in the uniformityof the quality autostereoscopic image across the width of the displayare desired.

BRIEF SUMMARY

The present disclosure relates to autostereoscopic displays that includea Fresnel lens element. The Fresnel lens element is disposed between adouble-sided prism film and the viewer to converge light toward theviewer.

In a first embodiment, the autostereoscopic display apparatus includes abacklight having opposing first and second light input surfaces and alight transmission surface extending between the opposing first andsecond light input surfaces and a right eye light source located toprovide light into the first light input side and a left eye lightsource located to provide light into the second light input side,wherein the left eye light source and the right eye light source areconfigured to be modulated between the left eye light source and theright eye light source at a rate of at least 90 hertz. A double sidedprism film is adjacent to the light transmission surface. The doublesided prism film has a plurality of linear prism features on a firstmajor surface and a plurality of lenticular features on a second majorsurface. The first major surface opposes the second major surface. Thedouble sided prism film is disposed between the light transmissionsurface and a Fresnel lens. A liquid crystal display panel is positionedto receive light transmitted through the double sided prism film.

In another embodiment, an autostereoscopic display apparatus includes abacklight, a double sided prism film, a Fresnel lens, a liquid crystaldisplay panel, and a synchronization driving element. The backlightincludes opposing first and second light input surfaces and a lighttransmission surface extending between the opposing first and secondlight input surfaces and a right eye light source located to providelight into the first light input side and a left eye light sourcelocated to provide light into the second light input side. The left eyelight source and the right eye light source are configured to bemodulated between the left eye light source and the right eye lightsource at a rate of at least 90 hertz. The double sided prism film isadjacent to the light transmission surface, the double sided prism filmhas a plurality of linear prism features on a first major surface and aplurality of lenticular features on a second major surface, the firstmajor surface opposing the second major surface. The double sided prismfilm is disposed between the light transmission surface and the Fresnellens. A liquid crystal display panel is positioned to receive lighttransmitted through the double sided prism film. A synchronizationdriving element synchronizes activation and deactivation of the righteye image solid state light source and the left eye image solid statelight source with image frames displayed on the liquid crystal displaypanel.

In a further embodiment, an autostereoscopic display apparatus includesa backlight, a double sided prism film, a Fresnel lens, a liquid crystaldisplay panel, and a synchronization driving element. The backlightincludes opposing first and second light input surfaces and a lighttransmission surface extending between the opposing first and secondlight input surfaces and a right eye light source located to providelight into the first light input side and a left eye light sourcelocated to provide light into the second light input side. The left eyelight source and the right eye light source are configured to bemodulated between the left eye light source and the right eye lightsource at a rate of at least 90 hertz. The double sided prism film isadjacent to the light transmission surface, the double sided prism filmhas a plurality of linear prism features on a first major surface and aplurality of lenticular features on a second major surface, the firstmajor surface opposing the second major surface. A liquid crystaldisplay panel is positioned to receive light transmitted through thedouble sided prism film. A linear converging Fresnel lens element isdisposed between the double sided prism film and the liquid crystaldisplay panel. The Fresnel lens element has a facet side facing thedouble sided prism film. The facet side includes a plurality of linearfacets extending parallel to the lenticular features. The linearconverging Fresnel lens converges light transmitted through the doublesided prism film toward a viewer of the autostereoscopic displayapparatus. A synchronization driving element synchronizes activation anddeactivation of the right eye image solid state light source and theleft eye image solid state light source with image frames displayed onthe liquid crystal display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a schematic side view of an illustrative display apparatus;

FIG. 2A and FIG. 2B are schematic side views of the illustrative displayapparatus of FIG. 1 in operation;

FIG. 3 is a schematic side view of the illustrative display apparatus ofFIG. 1 including a Fresnel lens element;

FIG. 4 is a cross-sectional view of a portion of the double sided prismfilm and Fresnel lens; and

FIG. 5 is a nomogram illustrating the effect of the Fresnel lens elementon autostereoscopic display viewing distance.

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part hereof, and in which are shown by way ofillustration several specific embodiments. It is to be understood thatother embodiments are contemplated and may be made without departingfrom the scope or spirit of the present invention. The followingdetailed description, therefore, is not to be taken in a limiting sense.

All scientific and technical terms used herein have meanings commonlyused in the art unless otherwise specified. The definitions providedherein are to facilitate understanding of certain terms used frequentlyherein and are not meant to limit the scope of the present disclosure.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein.

The recitation of numerical ranges by endpoints includes all numberssubsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, and 5) and any range within that range.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise. As used inthis specification and the appended claims, the term “or” is generallyemployed in its sense including “and/or” unless the content clearlydictates otherwise.

The term “autostereoscopic” refers to displaying three-dimensionalimages that can be viewed without the use of special headgear or glasseson the part of the user or viewer. These methods produce depthperception in the viewer even though the image is produced by a flatdevice. The term stereoscopic 3D incorporates the field ofautostereoscopic devices but also includes the stereoscopic 3D displaycase in which special headgear, e.g. shutter glasses or polarizedglasses, are need to see stereoscopic 3D from a flat display.

A liquid crystal display is a sample and hold display device such thatthe image at any particular point is stable until that point or pixel isupdated at the next image refresh time, typically within 1/60 of asecond or faster. In such a sample and hold system, displaying differentimages, specifically alternating left and right images for a 3D display,during sequential refresh periods of the display requires carefulsequencing of the backlight light sources so that, for example, the lefteye light source is not on during the display of data for the right eyeand vice versa.

The present disclosure relates to autostereoscopic displays that includea Fresnel element. The Fresnel element is disposed between adouble-sided prism film and the viewer to converge light toward theviewer. A converging linear Fresnel lens is placed between an LCD paneland a directional backlight (e.g., lightguide and two-sidedprism/lenticular film) illumination system to converge the lightdistribution from the entire display surface at the viewer position.Directional illumination systems without a Fresnel lens work well forsmall displays where the angle between the edge and center of thedisplay at the viewer position is small. However, in larger displaysonly the display center produces a good time sequential autostereoscopicimage because the left and right eye images from the display edges arenot converged to the viewer. By adding the Fresnel lens element, muchlarger convergence angles are possible and enable larger 3D displays.While the present invention is not so limited, an appreciation ofvarious aspects of the invention will be gained through a discussion ofthe examples provided below.

FIG. 1 is a schematic side view of an illustrative stereoscopic displayapparatus 10. The display apparatus includes a liquid crystal displaypanel 20 having a frame response time of less than 10 milliseconds, orless than 5 milliseconds, or less than 3 milliseconds, and a backlight30 positioned to provide light to the liquid crystal display panel 20.

The backlight 30 includes a light transmission surface 35 and opposinglight input surfaces 31, 33. A right eye image solid state light source32 injects light into a first light input surface 31 and a left eyeimage solid state light source 34 injects light into a second lightinput surface 31. The right eye image solid state light source 32 andthe left eye image solid state light source 34 are capable of beingmodulated between the right eye image solid state light source 32 andthe left eye image solid state light source 34 at a rate of at least 90Hertz. A double sided prism film 40 is disposed between the liquidcrystal display panel 20 and the backlight 30.

The liquid crystal display panel 20 and/or backlight 30 can have anyuseful shape or configuration. In many embodiments, the liquid crystaldisplay panel 20 and backlight 30 has a square or rectangular shape.However, in some embodiments, the liquid crystal display panel 20 and/orbacklight 30 has more than four sides or is a curved shape. While FIG. 1is directed to any stereoscopic 3D backlight including those requiringshutterglasses or more than a single lightguide and associated liquidcrystal display panel, the present disclosure is particularly useful forautostereoscopic displays. In other embodiments, the display is an OLEDdisplay, a plasma display, and the like.

A synchronization driving element 50 is electrically connected to thebacklight 30 light sources 32, 34 and the liquid crystal display panel20. The synchronization driving element 50 synchronizes activation anddeactivation (i.e., modulation) of the right eye image solid state lightsource 32 and the left eye image solid state light source 34 as imageframes are provided at a rate of 90 frames per second or greater to theliquid crystal display panel 20 to produce a flicker-free still imagesequence, video stream or rendered computer graphics. An image (e.g.,video or computer rendered graphics) source 60 is connected to thesynchronization driving element 50 and provides the images frames (e.g.,right eye images and left eye images) to the liquid crystal displaypanel 20.

The liquid crystal display panel 20 can be any transmissive liquidcrystal display panel that has a frame response time of less than 10milliseconds, or less than 5 milliseconds. Commercially availabletransmissive liquid crystal display panels having a frame response timeof less than 10 milliseconds, or less than 5 milliseconds, or less than3 milliseconds, are for example Toshiba Matsushita Display's (TMD)optically compensated bend (OCB) mode panel LTA090A220F (ToshibaMatsushita Display Technology Co., Ltd., Japan).

The backlight 30 can be any useful backlight that can be modulatedbetween a right eye image solid state light source 32 and left eye imagesolid state light source 34 at a rate of at least 90 Hertz, or 100Hertz, or 110 Hertz, or 120 Hertz, or greater than 120 Hertz. Theillustrated backlight 30 includes a first light input surface 31adjacent to the right eye image solid state light source 32 and anopposing second light input surface 33 adjacent to the left eye imagesolid state light source 34 and a light output surface 35. The solidstate light sources can be any useful solid state light source that canbe modulated at a rate of at least 90 Hertz. In many embodiments, thesolid state light source is a plurality of light emitting diodes suchas, for example, Nichia NSSW020B (Nichia Chemical Industries, Ltd.,Japan). In other embodiments, the solid state light source is aplurality of laser diodes or organic light emitting diodes (i.e.,OLEDs). The solid state light sources can emit any number of visiblelight wavelengths such as white, red, blue, and/or green. The backlightcan be a single layer of optically clear material with light sources atboth ends or two (or more) layers of optically clear material with alight source per layer which preferentially extract light in a desireddirection for each layer.

The double sided prism film 40 can be any useful prism film having alenticular structure on a first side and a prismatic structure on anopposing side. The double sided prism film 40 transmits light from thebacklight to the liquid crystal display panel 20 at the proper anglessuch that a viewer perceives depth in the displayed image. Useful,double sided prism films are described in United States PatentPublication Nos. 2005/0052750 and 2005/0276071, which are incorporatedherein to the extent they do not conflict with the present disclosure.These double sided prism films have an open angle of about 60 degreesand provide image separation of approximately equal to the distancebetween a viewer's eyes (i.e., about six degrees).

The image source 60 can be any useful image source capable of providingimages frames (e.g., first image view and left image views) such as, forexample, a video source or a computer rendered graphic source. In manyembodiments, the video source can provide image frames from 50 to 60Hertz or greater. In many embodiments, the computer rendered graphicsource can provide image frames from 100 to 120 Hertz or greater.

The computer rendered graphic source can provide gaming content, medicalimaging content, computer aided design content, and the like. Thecomputer rendered graphic source can include a graphics processing unitsuch as, for example, an Nvidia FX5200 graphics card, a Nvidia GeForce9750 GTX graphics card or, for mobile solutions such as laptopcomputers, an Nvidia GeForce GO 7900 GS graphics card. The computerrendered graphic source can also incorporate appropriate stereo driversoftware such as, for example, OpenGL, DirectX, or Nvidia proprietary 3Dstereo drivers.

The video source can provide video content. The video source can includea graphics processing unit such as, for example, an Nvidia Quadro FX1400graphics card. The video source can also incorporate appropriate stereodriver software such as, for example, OpenGL, DirectX, or Nvidiaproprietary 3D stereo drivers.

The synchronization driving element 50 can include any useful drivingelement providing synchronizing activation and deactivation (i.e.,modulation) of the right eye image solid state light source 32 and theleft eye image solid state light source 34 with image frames provided ata rate of 90 frames per second or greater to the liquid crystal displaypanel 20 to produce a flicker-free video or rendered computer graphics.The synchronization driving element 50 can include a video interfacesuch as, for example, a Westar VP-7 video adaptor (Westar DisplayTechnologies, Inc., St. Charles, Mo.) coupled to custom solid statelight source drive electronics.

FIG. 2A and FIG. 2B are schematic side views of an illustrativestereoscopic display apparatus 10 in operation. In FIG. 2A the left eyeimage solid state light source 34 is illuminated and the right eye imagesolid state light source 32 is not illuminated. In this state, the lightemitted from the left eye image solid state light source 34 transmitsthrough the backlight 30, through the double sided prism sheet 40, andliquid crystal panel 20 providing a first image view (i.e., left eyeimage) directed toward the left eye 1 a of an viewer or observer.

In FIG. 2B the right eye image solid state light source 32 isilluminated and the left eye image solid state light source 34 is notilluminated. In this state, the light emitted from the right eye solidstate light source 32 transmits through the backlight 30, through thedouble sided prism sheet 40, and liquid crystal panel 20 providing asecond image view (i.e., right eye image) directed toward the right eye1 b of an viewer or observer.

Providing at least 45 left eye images and at least 45 right eye images(alternating between right eye and left eye images and the images arepossibly a repeat of the previous image pair) to a viewer per secondprovides a flicker-free 3D image to the viewer. Accordingly, displayingdifferent right and left viewpoint image pairs from computer renderedimages or images acquired from still image cameras or video imagecameras, when displayed in synchronization with the switching of thelight sources 32 and 34, enables the viewer to visually fuse the twodifferent images, creating the perception of depth from the flat paneldisplay. A limitation of this visually flicker-free operation is that,as discussed above, the backlight should not be on until the new imagethat is being displayed on the liquid crystal display panel hasstabilized, otherwise cross-talk and a poor stereoscopic image will beperceived.

FIG. 3 is a schematic side view of the illustrative display apparatus 10of FIG. 1 including a Fresnel lens element 50. The display apparatusincludes a liquid crystal display panel 20, and a backlight 30positioned to provide light to the liquid crystal display panel 20, asdescribed above. The backlight 30 includes a light transmission surface35 and opposing light input surfaces 31, 33 and a right eye image solidstate light source 32 injects light into a first light input surface 31and a left eye image solid state light source 34 injects light into asecond light input surface 31. The right eye image solid state lightsource 32 and the left eye image solid state light source 34 are capableof being modulated between the right eye image solid state light source32 and the left eye image solid state light source 34 at a rate of atleast 90 Hertz. A double sided prism film 40 is disposed between theliquid crystal display panel 20 and the backlight 30, as describedabove.

The Fresnel lens element 50 is disposed proximate to the double sidedprism film 40. The double sided prism film 40 is disposed between thelight transmission surface 35 of the backlight 30 and Fresnel lenselement 50. In many embodiments, the Fresnel lens element 50 is disposedbetween the liquid crystal display panel 20 and the double sided prismfilm 40, as illustrated in FIG. 3. In other embodiments, the Fresnellens element 50 is disposed to accept light transmitted by the liquidcrystal display panel 20. In these embodiments, the liquid crystaldisplay panel 20 is disposed between the double sided prism film 40 andthe Fresnel lens element 50, as illustrated in phantom in FIG. 3. TheFresnel lens element 50 converges light transmitted from the doublesided prism film 40 toward the viewer of the display 10.

The Fresnel lens element 50 includes a plano side 52 and a facet side(i.e., grooved side) 54. In many embodiments, the facet side 54 of theFresnel lens element 50 is directed toward the double sided prism film40 and the plano side 52 is directed toward the liquid crystal displaypanel 20 or viewer of the display 10. The Fresnel lens element 50 isdescribed as a converging Fresnel lens element 50 as the Fresnel lenselement 50 converges light toward the viewer of the display 10.

In many embodiments the Fresnel lens element 50 is a linear Fresnel lenselement 50 that includes a plurality of parallel linear facets thatextend linearly along a width of the display 10. In many embodiments,the Fresnel lens element 50 is a linear converging Fresnel lens element50. In many embodiments the Fresnel lens element 50 is a linear Fresnellens element 50 that includes a plurality of parallel linear facets thatextend linearly along a width of the display 10 and are parallel to thelinear lenticular features and linear prismatic features of the doublesided prism film 40. In some embodiments the Fresnel lens element 50 isa linear Fresnel lens element 50 that includes a plurality of parallellinear facets that extend linearly along a width of the display 10 andare parallel to the linear lenticular features of the double sided prismfilm 40 and are in registration with a plurality of linear lenticularfeatures of the double sided prism film 40.

In many embodiments, the Fresnel lens element 50 has a varying focallength as a function of location along the Fresnel lens element 50.Thus, in some embodiments a location along an edge of the Fresnel lenselement 50 can have a shorter focal length than a location closer to acenter of the Fresnel lens element 50.

FIG. 4 is a cross-sectional view of a portion of the double sided prismfilm 40 and Fresnel lens element 50. The Fresnel lens element 50includes a plano side 52 and a grooved facet side 54, as describedabove. The double sided prism film 40 includes plurality of parallellinear prism features 44 on a first major surface and a plurality ofparallel linear lenticular features 42 on a second major surfaceopposing the second major surface.

The plurality of parallel linear prism features 44 have a pitch P_(P)value and the plurality of parallel linear lenticular features 42 have apitch P_(L) value. The pitch P_(L) value is defined as the lineardistance between lenticular valleys 43. The pitch P_(P) value is definedas the linear distance between prism valleys 46. In many embodiments thepitch P_(P) value is greater than the pitch P_(L) value. In manyembodiments this difference in pitch is very small such as, for example,in a range from 0.001 to 0.2%, or from 0.01 to 0.1%. This difference inpitch for a double sided prism film 40 is termed herein a “differentialpitch” double sided prism film 40. In many embodiments, lenticularfeatures 42 are nominally aligned with prism features 44 at a centerregion of the double sided prism film 40 and the opposing features 42,44 become more misaligned as the distance from the center of the filmincreases. This differential pitch double sided prism film 40 allows thefilm to gradually increase the “toe-in” of light as a function of thedistance from the center of the double sided prism film 40. In many ofthese embodiments the maximum light “toe-in” is 10 degrees at the edgeof the differential double sided prism film 40.

FIG. 5 is a nomogram illustrating the effect of the Fresnel lens elementon autostereoscopic viewing distance. The nomogram illustrates thatadding a Fresnel lens element to the autostereoscopic display devicedescribed herein allows 3D viewing of larger displays than is possiblewithout the Fresnel lens element. The aspect ratio of the display wasset to 16:10.

The solid line is labeled “differential” and refers to anautostereoscopic display as illustrated in FIG. 1 with the differentialpitch double sided prism film described in FIG. 4. The maximum lighttoe-in angle for this differential pitch double sided prism film was 10degree. As illustrated, a viewing distance of 1000 mm allows for adisplay diagonal of about 450 mm.

The doted line is labeled “Fresnel” and refers to an autostereoscopicdisplay as illustrated in FIG. 1 without the differential pitch doublesided prism film described in FIG. 4. The maximum light angle of theFresnel lens element was 25 degrees. The facet side groove pitch was setto 0.088 mm, the plano side conjugate was set to 1×10⁹ mm, the facetside conjugate was set to 500 mm, the half width was set to 200 mm, andthe draft angle was set to 4 degrees. As illustrated, a viewing distanceof 1000 mm allows for a display diagonal of about 1000 mm.

The alternating doted line is labeled “Differenital+Fresnel” and refersto an autostereoscopic display as illustrated in FIG. 1 with thedifferential pitch double sided prism film described in FIG. 4. Themaximum light toe-in angle for this differential pitch double sidedprism film was 10 degree. The maximum light angle of the Fresnel lenselement was 25 degrees. The facet side groove pitch was set to 0.088 mm,the plano side conjugate was set to 1×10⁹ mm, the facet side conjugatewas set to 500 mm, the half width was set to 200 mm, and the draft anglewas set to 4 degrees. As illustrated, a viewing distance of 1000 mmallows for a display diagonal of about 1600 mm.

The nomogram illustrates that adding a Fresnel lens element and thedifferential pitch double sided prism film to the autostereoscopicdisplay device described herein allows 3D viewing of larger displaysthan is possible with or without the Fresnel lens element ordifferential pitch double sided prism film.

Thus, embodiments of the AUTOSTEREOSCOPIC DISPLAY WITH FRESNEL LENSELEMENT are disclosed. One skilled in the art will appreciate that thepresent invention can be practiced with embodiments other than thosedisclosed. The disclosed embodiments are presented for purposes ofillustration and not limitation, and the present invention is limitedonly by the claims that follow.

1. An autostereoscopic display apparatus comprising: a backlight havingopposing first and second light input surfaces and a light transmissionsurface extending between the opposing first and second light inputsurfaces and a right eye light source located to provide light into thefirst light input side and a left eye light source located to providelight into the second light input side, wherein the left eye lightsource and the right eye light source are configured to be modulatedbetween the left eye light source and the right eye light source at arate of at least 90 hertz; a double sided prism film adjacent to thelight transmission surface, the double sided prism film having aplurality of linear prism features on a first major surface and aplurality of lenticular features on a second major surface, the firstmajor surface opposing the second major surface; a Fresnel lens element,wherein the double sided prism film is disposed between the lighttransmission surface and the Fresnel lens element; and a display panelpositioned to receive light transmitted through the double sided prismfilm, wherein the display panel is an organic light emitting diode(OLED) display panel.
 2. An autostereoscopic display apparatuscomprising: a backlight having opposing first and second light inputsurfaces and a light transmission surface extending between the opposingfirst and second light input surfaces and a right eye light sourcelocated to provide light into the first light input side and a left eyelight source located to provide light into the second light input side,wherein the left eye light source and the right eye light source areconfigured to be modulated between the left eye light source and theright eye light source at a rate of at least 90 hertz; a double sidedprism film adjacent to the light transmission surface, the double sidedprism film having a plurality of linear prism features on a first majorsurface and a plurality of lenticular features on a second majorsurface, the first major surface opposing the second major surface; aFresnel lens element, wherein the double sided prism film is disposedbetween the light transmission surface and the Fresnel lens element; anda display panel positioned to receive light transmitted through thedouble sided prism film, wherein the left eye light source and the righteye light source each comprise one or more OLED sources.
 3. Anautostereoscopic display apparatus comprising: a curved backlight havingopposing first and second light input surfaces and a light transmissionsurface extending between the opposing first and second light inputsurfaces and a right eye light source located to provide light into thefirst light input side and a left eye light source located to providelight into the second light input side, wherein the left eye lightsource and the right eye light source are configured to be modulatedbetween the left eye light source and the right eye light source at arate of at least 90 hertz; a double sided prism film adjacent to thelight transmission surface, the double sided prism film having aplurality of linear prism features on a first major surface and aplurality of lenticular features on a second major surface, the firstmajor surface opposing the second major surface; a Fresnel lens element,wherein the double sided prism film is disposed between the lighttransmission surface and the Fresnel lens element; and a curved displaypanel positioned to receive light transmitted through the double sidedprism film.
 4. An autostereoscopic display apparatus according to claim3, wherein the display panel is a liquid crystal display panel.
 5. Anautostereoscopic display apparatus according to claim 3, wherein thedisplay panel is an OLED display panel.
 6. An autostereoscopic displayapparatus according to claim 3, wherein the left eye light source andthe right eye light source each comprise one or more OLED sources.